Below Grade Insulation

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“EPS - The Safe Insulation”

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Busting The Insulation Myths
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EPS vs XPS

For years we have been told that XPS (Extruded Polystyrene) insulation is not as good as the other insulation….

Is this true?
What about the new research?

  • R-Value
  • Water Absorption
  • Building Codes
  • Strength
  • Is EPS Green
  • LTTR
  • XPS vs EPS
Tab 1
Myth: XPS has a higher R-Value than EPS - below grade
Not Exactly True
Compare 25 PSI (250) Product R-Value
XPS 250
EPS 250
Published R-Value Per Inch*
5
4.35
Guaranteed R-Value Per Inch*
4.5
4.35
Field Study R-Value Per Inch*
2.6
4.09
Real World Results Matter
  • Field studies mirror real world resultsFor years XPS foam was the choice and recommendation for below grade insulation, but after a 15 year study was conducted by an independent Test Lab (In-Situ), EPS foam significantly outperformed XPS foam not only in its retention of its R-value but also showed superior properties in decreased water absorption.
  • Published R-Value reflect perfect laboratory conditions As a starting point, published ASTM results is important for product comparison. Unfortunately, these results are under perfect lab conditions and not real world conditions. Real world variables are numerous, however independent research over long periods in real conditions should be highly favored in design considerations.
  • Performance is what you pay for. The dramatic difference in long-term insulation performance is so significant that Architects, Engineers, Contractors, Builders, Building Inspectors and Home Owners should be aware of these test results and true facts when determining which insulation would offer the most long term insulation value and energy savings. EPS continues to be the best insulation value. EPS Cost/R-Value inch vs XPS can be as much as 50% better considering field studies. This only the initial cost of material and not even taking into account long-term operational performance costs.
  • Show More
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* Published R-Values come directly from the manufacturer’s publications. XPS R-values were used from Owens Corning and Dow. Guaranteed R-value was from XPS Manufactures publication - See Warranties. Field Study R-values where extrapolated from In-Suit Research and for comparative analysis purposes only.
Tab 2
Myth: XPS absorbs and retains less moisture than EPS - below grade
Field study says - Not true
Compare Water Absorption by % XPS VS EPS
XPS
EPS
Published Water Absorption by Total Immersion
0.3%
2%
Field Study R-Value Per Inch*
18.9%
4.8%
“Having accurate data is a key ingredient in choosing the proper insulation for your foundation wall because it not only effects the entire energy efficiency of the building but also the dryness. “
Real Science
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EPS Stands Out

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Real science conducted in real world application provide quite a difference. These results suggest very clearly that short term laboratory tests of water absorption for XPS does not necessarily reflect the long term below grade performance of these materials.
Additional Interest Facts About Water Retention
EPS Dries Out
One of the great properties of EPS is that water that is absorb can expel out. EPS insulation exhibited drying potential under severe exposure conditions while XPS, when exposed to the same conditions, did not. Read More
EPS Hold R-Value Even When Wet
EPS foam will maintain its R-value, even with significant saturation percentages. In contrast, Extruded Polystyrene (XPS) foam is more dramatically affected by small amounts of moisture. Read More
Freeze-Thaw No Loss R-Value or Strength
These independent tests confirm the freeze‐thaw and moisture resistance properties of EPS insulation. Test results confirm no loss in R‐value or change in compressive strength for EPS. Read More
The long‐term application of XPS insulation below grade results in a higher water retention and greater loss of R‐value than reported when using standardized laboratory test methods. Water absorption results for XPS using ASTM C272 cannot be correlated to the in‐service performance of extruded polystyrene foam insulation.
Tab 3
Myth: EPS is not code approved as a building product
False - It is approved
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Expanded Polystyrene (EPS),
as a building material is
recognized and approved
to be used as an insulation product.

Plymouth Foam is approved
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Tab 4
Myth: EPS is not as strong
False - EPS has many various densities up to 8,640 PSF. In Fact, EPS And XPS Insulation use the same measuring stick for strength - ASTM D1621.
EPS mechanical strength varies with its selected density or type. One way to determine the strength of EPS is by measuring its “Compressive Resistance” or capability for materials to withstand loads. EPS having resistance to compressive stress is one the most important property of a building products. In fact, Plymouth Foam’s EPS compressive resistance can vary from 1,440 - 8,640 psf at 10% strain deformation (ASTM D 1621). Design considerations should be made as to which EPS type is needed or required.
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Flexural Strength is another measurement used to determine how “durable or brittle” a product performance might be. Flexural strength is really determining its “bending strength.” EPS insulation is used in most application as a filler not a pure structural product but it is good to know the flexural strength of a product.
Note: Exposure of EPS to moisture resulting from such factors as periodic, internal condensation or moist soil conditions in foundation applications do not affect the mechanical strength characteristics of EPS thermal insulation board. 
Tab 5
Myth: EPS is not a Green product and clogs landfills
False - EPS is very Green

100% Recyclable

Post Consumer EPS Recycling Rates

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Facts

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2013 - over 127 Million Pounds of EPS was recycled
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2013 - over 34% of post consumer EPS was recycled
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2013 - less than .003% of total waste in landfills is EPS and most of that could have been recycled
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98% of EPS contains regular air, which is what we breath, and 2% carbon and hydrogen

Responsible, Low Impact Manufacturing

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Steam is used as energy in the manufacturing of EPS. The steam itself is produced in boilers mainly using natural gas as fuel. Water consumption used in the manufacture of EPS is very low. The water is reused many times in the process.
There is no solid waste generated during the EPS manufacturing process. Waste and off-cuts are easily put back into the
production process. No material is wasted and clean EPS can be recycled into new product using this method.
There is no pollution to the surface or underground water supplies near an EPS plant because atmospheric and liquid
emissions are very low during the manufacture of EPS.
EPS is very light to transport as 98% of the product is air. Fuel saving is realized due to the reduction in load weight.
Note: According to the Department of Energy (DOE): “Beyond the environmental benefits of the installed product, the energy requirements to make polystyrene can be more favorable than some alternative materials. In one study, when compared to fiberglass insulation, the energy required to produce polystyrene insulation is 24 percent less than what is needed to make the amount of fiberglass needed to achieve an equivalent R-value at a representative volume”.

Health and Safety

During Production
During the manufacturing of Expanded Polystyrene, emission levels are very low due in part to the fact that “air” makes up 98% of its volume. Much research has been done on the raw material styrene and has been found to be perfectly safe in normal uses. Polystyrene has a maximum styrene content of only 0.1% by weight, and since EPS contains only 2% polystyrene by volume, this minute trace of styrene monomer poses no threat to health whatsoever.

A small amount of pentane is incorporated into the expandable polystyrene granules as a expanding agent. It is a saturated hydrocarbon, not to be confused with HCFCs and CFCs. Pentane is non-toxic and constitutes no threat to the ozone layer.

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Building products require some type of fire retardant in them by law. The EPS industry has been using hexabromocyclododecane (HBCD) as a fire retarder for years and is in such a minute quantity ( .5% by weight) that it has been shown not to cause any health risks. Opponents to the EPS industry have tried to make HBCD sound like enemy #1, however they do not tell you that HBCD remains within the closed cells of EPS and does not dissolve in water. The real question is whether adding in any type of fire retardant into a product is worth the additional cost, as well as any other risks? In response to ongoing questions about the ecological safety of HBCD, even though 10 studies have concluded, “HBCD is not entering the environment in a quantity or under conditions that constitute a risk to human health, the chemical industry has announced the development of an innovative flame retardant (FR) that may be suitable alternative for use in expanded polystyrene (EPS) foam. An Action Plan is forming to determine the best course of action for the industry. Learn More
During Construction
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EPS has long been considered a pleasant material to work with. Unlike other foam materials that have fibers that cause skin itching or stick to the skin, EPS is safe to handle. Another benefit of EPS in respect to safety, health and well-being is its exceptional light weight. No heavy equipment to mix it or blow it in the field. EPS is easy to cut and very easy to install.

During Use and Indoor Enviroment
Unlike other insulations, EPS does not off-gas but rather holds its R-value which provides good indoor air quality. EPS offers superior mold and mildew resistance as well as good thermal resistance which helps to provide comfortable land healthy living. Good materials and good construction can lead to extended building life and can reduce landfill waste helping the enviroment. Even during restoration, renovation or demolition, EPS continues to be a safe building material.
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EPS Green Building Credits
EPS can contribute to achieving green building ratings in the following categories.
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ENERGY & ATMOSPHERE
  • EPS insulation facilitates compliance with ASHRAE 90.1-2004.
  • EPS can be manufactured in a variety of densities and thicknesses to meet environmental design criteria to deliver a range of R-value specifications.
  • EPS has always been CFC and HCFC free.
  • EPS is the only rigid foam insulation that provides long-term thermal resistance that does not need to be adjusted for age.
  • EPS building systems reduce air leakage for increased thermal efficiency.
MATERIALS & RESOURCES
  • Recycled content EPS that meets ASTM C578 minimum performance properties can be specified for rigid foam insulation.
  • Recycled content polystyrene can be specified when procuring plastic lumber, interior trim, lightweight concrete, asphalt aggregate and other building products.
  • Plymouth Foam EPS is manufactured locally, minimizing its distribution radius. Because it is lightweight EPS reduces transportation costs and energy.
INDOOR ENVIRONMENTAL QUALITY (IEQ)
  • EPS is not known to adversely affect indoor air quality.
  • EPS mold resistance tests favorably in accordance with ASTM C1338.
  • EPS building systems can prevent noise transmission, resulting in quieter buildings.
  • EPS insulation helps maintain a consistent air temperature.
SUSTAINABLE SITES
  • EPS insulation reduces impacts on the microclimate.
  • EPS geofoam maintains ecological integrity and reduces erosions through soil stabilization.
  • EPS frost protected shallow foundations (FPSF’s) minimize excavation below the frost line and are ideal for sites with high groundwater table.
Tab 6
Myth: LTTR is the true R-value of my insulation
Yes and No
Extruded Polystyrene and Polyisocyanurate Insulation
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Off Gassing
During the manufacturing process of Extruded Polystyrene (XPS) and Polysisocyanurate (ISO) insulation a gas blowing agent is formed into the cells. This insulation gas provides a initial higher resistance or higher R-value. (This concept is similar to using Argon gas in windows.) Starting immediately after the insulation is produced, a chemical transformation (Off Gassing) happens allowing this trapped gas to starts migrating from the insulation cells. This migration of gasses lowers the R-Value of the insulation over time.

You have seen this concept of Off Gassing before in Helium Balloons. When the party is over, those floating balloons are now down on the ground the next morning. Why? The helium gas has migrated out of the balloon.
The Shrinking R-Value
The off gassing of XPS and ISO is not just a one time event. This loss is a gradual escape of gasses into the surrounding environment. With the gasses goes the R-value loss of the insulation as well. We know that ISO starts out around 7 r/inch and after five years is at the 5.6 r/inch mark. The real question is how much does it go down, how fast and over what period. Long Term Thermal Performance (LTTR), does not take into account the shrinking R-value after the first 5 years. (Learn More)

Buildings are designed and built to last 50-100 years in most cases. If LTTR only gives use a clear picture of the first 5 years of insulation performance, how does that information effect the economies of the building? Does it cost more to operate than expected? Did we over pay for a insulation that has a shrinking R-value? Are their long-term health impacts from the off gassing?
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The Great Alternative - Expanded Polystyrene
Unlike ISO and XPS insulation, Expanded Polystyrene (EPS) does not suffer from off gassing or thermal drift like the others. EPS rigid insulation does not derive its R-value from trapped gasses. It traps regular atmospheric air. Air can be replace by air due to any migration but has no effect on R-value. EPS’s R-value staying consistent provides a huge financial benefit for years. Building Energy Models are consistent and more accurate. With EPS, what you pay for in R-value is what you get. The remaining fact is that EPS is the best value in regards to r-value/inch. Learn More

We believe that higher priced rigid insulation, that losses much of its thermal residence over time, is not a good value or investment.
See Chart

“EPS - The Safe Insulation”

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“EPS - The Great Investment”

Tab 7
Myth: XPS is Superior to EPS
False - EPS has more advantages over XPS

For years we have been told that XPS (Extruded Polystyrene) rigid insulation is better than EPS (Expanded Polystyrene) in many applications. New research has revealed new information about water absorption in both  types of polystyrene insulation. Now we know EPS insulation is far superior to XPS insulation.

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Why is EPS Insulation Superior

Engineered EPS Has The Advantages
Which insulation is the best
The Facts

Compressive Resistance at 10%

Compressive Resistance testing is a method that provides information regarding the behavior of cellular materials under compressive loads. Both EPS and XPS have the ability, through densities, to provide a range of compressive resistant properties. 25 PSI material is the most commonly specified property and both EPS and XPS meet that specification.

Exposure of EPS to moisture resulting from such factors as periodic, internal condensation or moist soil conditions in foundation applications do not affect the mechanical strength characteristics of EPS thermal insulation board.
EPS Insulation has a 25 PSI rating in Type IX
XPS and EPS are EQUAL in Compressive Resistance strength.

Higher R-Value Rentention

EPS does not suffer from the same plight as XPS in regards to “Off Gassing.” XPS has blowing agents that initial give it a higher R-value, but these gasses escape over time lowering the R-value. The off gassing of XPS is not just a one time event. This loss is a gradual escape of gasses into the surrounding environment. With the gasses goes the R-value loss of the insulation as well. The real question is how much does it go down, how fast and over what period. Long Term Thermal Performance (LTTR), is a measurement to try and quantify these losses but it does not take into account the shrinking R-value after the first 5 years. (Learn More About LTTR)

Buildings are designed and built to last 50-100 years in most cases. If LTTR only gives use a clear picture of the first 5 years of insulation performance, how does that information effect the economies of the building? Does it cost more to operate than expected? Did we over pay for a insulation that has a shrinking R-value? Are their long-term health impacts from the off gassing? (
News About LTTR)
Off Gassing
Off Gasing in Insulation
Lowers R-Value in Insulation

Harmful Chemical HCFC

Hydro-chlorofluorocarbons (HCFCs) are listed as a Volatile Organic Compound (VOC). XPS contains HCFC, EPS does not. As a VOC, HCFCs may be involved in reactions to produce ozone, which can cause damage to plants and materials on a local scale. At a global level however, releases of HCFCs have serious environmental consequences. Although not as stable and therefore not so persistent in the atmosphere as CFCs, HBFCs or Halons, they can still end up in the higher atmosphere (stratosphere) where they can destroy the ozone layer, thus reducing the protection it offers the earth from the sun's harmful UV rays. HCFCs also contribute to Global Warming (through "the Greenhouse Effect"). Although the amounts emitted are relatively small, they have a powerful warming effect (a very high "Global Warming Potential").

Some VOCs are dangerous to human health and breathing in these compounds have not been fully studied or understood as to the effects on human health. (More About VOCs)

No HCFC in EPS Insulation
EPS does not
contain HCFCs

Greater R-Value Actuality

Which are more valuable R-value numbers - in a lab or where they are actually being used? As a starting point, published ASTM results is important for product comparison. Unfortunately, these results are under perfect lab conditions and not real world conditions. Real world variables are numerous, however independent research over long periods in real conditions should be highly favored in design considerations.

In a 15 year study that was conducted by an independent test lab, XPS and EPS was put to the test in real world conditions. EPS foam significantly outperformed XPS foam not only in its retention of its R-value but also showed superior properties in decreased water absorption.
R-Value Retention

EPS better real world R-value

100% R-Value Warranty

XPS warranties 90% of its R-value. EPS warranties 100% of its R-value. These of course are under the conditions of the warranties. (see XPS Warranties) The reason for the differences is really the Off gassing and the dropping of the R-value in XPS insulation. EPS does not suffer from dropping R-value, therefore it can give the full 100%.

* Published R-Values come directly from the manufacturer’s publications. XPS R-values were used from Owens Corning and Dow. Guaranteed R-value was from XPS Manufactures publication - See Warranties.
Why get 90% when you can get 100% Warranty
Are you getting what you paid for?

XPS 90%
EPS 100%

Made in Wisconsin

Plymouth Foam’s EPS is proud to made in Wisconsin. Our state has one of the best educational system in the country and it shows in our workforce. We provide many local jobs and help boost our economy. (Made in Wisconsin)

Some of the XPS is made in China or other parts of the County. But Plymouth Foam is proud to say, our EPS insulation is Made in the USA.

Buy local  Made in Wisconsin and Made in the USA

and
Proud
of
it

Lower Global Warming Potential

The Global Warming Potential (GWP) was developed to allow comparisons of the global warming impacts of different gases. According to the US Environmental Protection Agency,” the larger the GWP, the more that a given gas warms the Earth compared to CO2. GWPs provide a common unit of measure, which allows analysts to add up emissions estimates of different gases.” (EPA - Green House Gas Emissions)

The chemical compound HCFCs contribute XPS having a higher GWP than EPS. Transportation accounts for 26% of gas emissions, so buying EPS locally can help reduce gasses even more. (
EPS Reduces Global Warming)
EPS Insulation can reduce harmful gas emissions

EPS helps reduced utility usage lower harmful gas emissions

Superior Bonding Capability

During the manufacturing process, XPS and EPS provide a far different exterior surface. XPS almost has a skin, which makes bonding to that skin less desirable. EPS on the other hand has a surface that excepts bonding very well. In fact, the Insulated Concrete Forms (ICFs), Exterior Insulated Finish System (EIFS) and the Structural Insulated Panels (SIPs) industries have found EPS to have exceptional bonding capability. These building components industries prefer EPS and believe the product is far superior to XPS. The packaging industry has also found EPS exceptional for component bonding. High end packaging prefers EPS because of its physical bonding capability.
EPS has better bonding capabilities

EPS is far superior in bonding capability to XPS

Lower Smoke Development

ASTM E84 is the test method for surface burning characteristics of building materials. This test covers flame spread and smoke development. Polystyrenes (XPS & EPS) have very similar characteristic when it comes to the introduction of fire. Flame spread is identical but EPS has a lower flame spread. Some would believe in simple terms that EPS is 98% air with no blowing agent. Both products do meet the IBC requirement for building products.
EPS insulation smoke development

Smoke development is slightly lower in EPS

More Customizable

The building industry is requiring more customization of products. The 4’ x 8’ sheets are ok, but more and more building professional are looking for more. Basement wall heights of 9’4” as an example, wouldn’t one piece covering the 9’4” height be better. EPS is far superior in its ability to make custom sizes, shapes and thicknesses. XPS is limited to 3” - 4” thick, where EPS can be made up to 48” thick. XPS is limited to R-15, where EPS can go up to R-209.

EPS can add lamination to its products, such as reflective facer in fan-fold. Tongue and grove, ship lap, groves, channels, wire case are just a few items that be added to EPS. The possibilities are almost endless with EPS. (
See More Customization of EPS)
EPS insulation can be custom made

The possibilities with EPS are almost Endless

Cost LESS

The difference in cost between XPS and EPS can range from 20% - 40%. EPS is always less, but more importantly it less per R-value inch as well. (by the numbers) In fact, EPS is the best value in rigid insulation.

Many building profession are learning the facts and costs of EPS and are starting to Value engineer projects (
Value Engineering EPS) Recently a contractor saved $1000 on a project by just switching from XPS to EPS. (See how he did it) With all these advantages, what is keeping you from using more EPS?
EPS insulation best price

Learn to Save with EPS

Note: EPS Type IX and XPS Type IV, both 25 psi material were compared

Disclaimer of Liability
Technical information contained herein is furnished without charge or obligation and is given and accepted at recipient’s sole risk. Because conditions of use may vary and are beyond our control, Go Plymouth Foam.com makes no representation about, and is not responsible or liable for the accuracy or reliability of data associated with particular uses of any product described herein.

Go Plymouth Foam.com believes the information and recommendations herein to be accurateand reliable. However, since use conditions are not within its control, Go Plymouth Foam.com does not guarantee results from use of such products or other information herein and disclaims all liability from any resulting damage or loss. No warranty, express or implied, is given as to the merchantability, fitness for particular purpose, or otherwise with respect to the products referred to.
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